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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 667 records · Page 37Linked to original sources
PubMed1988

Lymph flow during increases in pulmonary blood flow and microvascular pressure in dogs.

We studied the effects of an increase in pulmonary blood flow (PBF) on steady-state lung lymph flow (QL) and protein transport in anesthetized dogs (n = 7) to estimate the effect of vascular recruitment in zone 3 on transvascular filtration. At the end of each experiment, we increased left atrial pressure to 25-30 mmHg using a balloon catheter and obtained a washdown of the lymph protein concentration. PBF was increased with an extracorporeal circuit, which pumped blood from the left to the right atrium, and increases in pulmonary capillary pressure (Pc) were minimized by lowering left atrial pressure. PBF was measured by thermodilution, and Pc was measured by transient analysis of arterial occlusion pressure with a Swan-Ganz catheter. PBF increases averaged 78% with increases ranging from 36 to 118%. Pc increases ranged from 0.5 to 6.3 mmHg, and QL increases averaged 31% with changes ranging from -2 to +138%. We observed a 16% increase in QL for each 1-mmHg increase in Pc during increased PBF, which was comparable to the relationship previously observed after an increased left atrial pressure. Lymph-to-plasma total protein concentration ratios (CL/CP) decreased from 0.71 +/- 0.04 to 0.625 +/- 0.06 during increased PBF. The relationship between CL/CP, QL, and Pc for both increased blood flow and increased left atrial pressure were within the expected range for increased pressure alone. These data suggest that there was minimal vascular recruitment for transvascular filtration in zone 3 when pulmonary blood flow was increased. Microvascular filtration pressure was the main determinant of fluid and protein transvascular filtration under these conditions.

Animals↗
PubMed1988

Effects of the renin inhibitor A-64662 in monkeys and rats with varying baseline plasma renin activity.

The efficacy of the potent, primate selective renin inhibitor A-64662 was studied in monkeys and rats with varying baseline plasma renin activity (PRA) to elucidate the relationship between PRA and the hypotensive response induced by this compound. The effect of a single bolus of vehicle or A-64662 at 0.001, 0.01, 0.1, 1.0, and 10.0 mg/kg i.v. was compared in 30 normal and 30 salt-depleted, anesthetized monkeys (n = 5/dose). Baseline mean arterial pressure (MAP) was similar among all groups, but baseline PRA was elevated in salt-depleted monkeys. A-64662 induced a comparable dose-related fall in MAP, affecting the magnitude and duration of action, accompanied by inhibition of PRA, the duration of which was dose-related in both the normal and salt-depleted groups. However, the minimum effective doses required to reduce MAP by approximately 10% were 0.01 mg/kg for the salt-depleted monkeys and 0.1 mg/kg for the normal monkeys. In a second study, three consecutive boluses of vehicle or A-64662 at 0.1, 1.0, and 10.0 mg/kg were administered to anephric monkeys, human renin-infused anephric monkeys, and normal monkeys (n = 4/group). A dose of 0.1 mg/kg was ineffective, but the 1.0 mg/kg dose lowered MAP by 11 +/- 3% (mean +/- SE) in the anephric monkeys. The infusion of renin into anephric monkeys restored the efficacy of A-64662 at the 0.1 and 1.0 mg/kg doses to responses comparable to those of the normal monkeys. A-64662 at 10.0 mg/kg caused a similar fall in MAP of 50 to 60% in anephric, renin-infused anephric, and normal monkeys in the absence of detectable PRA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Fatal hemoptysis in acute bacterial endocarditis.

Massive hemoptysis is a rare complication of bacterial endocarditis. When seen, it is most often due to septic pulmonary emboli with infarction or rupture of a mycotic aneurysm of the pulmonary artery; these conditions are usually associated with endocarditis of the tricuspid valve. We report a case of fatal hemorrhage into the lung from a mycotic aneurysm of the subclavian artery, which eroded into the left upper lobe; this condition arose as a sequela of staphylococcal endocarditis involving the mitral valve.

Acute Disease↗
PubMed1988

Clinical and radiological aspects of dysplastic gangliocytoma (Lhermitte-Duclos disease): a report of two cases with review of the literature.

Two cases of Lhermitte-Duclos disease confirmed by biopsy are reported. Review of the 58 published cases shows that the disease can manifest itself only by signs of increased intracranial pressure. Cerebellar symptoms are not constant. Computed tomographic (CT) scans suggest the diagnosis by showing a posterior fossa lesion, iso- and hypodense, partially calcified, and not enhanced by contrast medium. Magnetic resonance imaging (MRI) seems to define limits of the lesion better than CT scanning and could improve the surgical approach. Surgical excision of the lesion is the only satisfactory treatment. The postoperative prognosis is usually favorable.

Adult↗
PubMed1988

Rapid sample preparation for determination of iron in tissue by closed-vessel digestion and microwave energy.

We developed a rapid acid-digestion method for preparing tissue samples for iron determination. Specimens were digested in nitric acid and hydrogen peroxide under high temperature and pressure in closed Teflon vessels, with microwave energy. Analysis for iron in 25- to 250-mg portions of digested bovine liver powder (National Bureau of Standards Certified Reference Material no. 1577a) showed excellent linearity ([predicted] = 1.007[actual] - 0.166 micrograms per sample) and analytical recovery (98%). Precision (CV) was 5.4% when iron content was 10 micrograms per sample. Assaying split samples of mouse tissues, we found a close correlation between iron concentrations obtained with closed vs open vessels ([closed] = 0.878[open] + 68 micrograms/g, r = 0.994, range 400-4600 micrograms/g dry weight). In contrast to time-consuming conventional procedures for tissue dissolution, closed-vessel digestion with microwave energy dramatically shortens time for tissue preparation, minimizes use of caustic acid, reduces risk of sample loss or contamination, and yields accurate and reproducible results.

Animals↗
PubMed1988

Cardiovascular actions of the primate-selective renin inhibitor, A-62198.

A-62198 [dimethylacetyl-Phe-His-NHCH(cyclohexylmethyl)CH-(OH)C H(OH)CH2N3] is a potent, selective inhibitor of primate renin. This compound induced a dose-dependent fall in mean arterial blood pressure (MAP) when administered as an i.v. bolus to anesthetized, salt-depleted monkeys. Both the magnitude and the duration of the hypotensive effect were dose related. Its actions were also studied during acute infusions in anesthetized anephric, normal and salt-depleted monkeys. MAP, heart rate and plasma renin activity (PRA) were determined during baseline and 30-min infusions of vehicle alone, followed by A-62198 as boluses of 0.01, 0.1 and 1.0 mg/kg, each maintained by infusing one-tenth of the bolus dose per minute. Vehicle did not alter base-line values. In the normal monkeys, A-62198 induced a dose-related fall in MAP which achieved statistical significance only at the highest dose, while maximally suppressing PRA at all doses (P less than .05, compared to vehicle). The salt-depleted monkeys responded with a dose-related fall in MAP and inhibition of PRA at all doses (P less than .05, compared to vehicle). A-62198 was relatively ineffective in the anephric monkeys which, as expected, had exceedingly low levels of PRA. Heart rate was unaltered regardless of dose or treatment group. Finally, infusion of 1.0 mg/kg bolus + 0.1 mg/kg/min of A-62198 had no effect on MAP or PRA in 2 kidney-1 clip rats, although MAP was reduced subsequent to a superimposed bolus of 0.1 mg/kg of captopril. We conclude that the renin inhibitor, A-62198, is an effective, primate selective hypotensive agent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[The osteocutaneous outer arm flap. A new concept in microsurgical mandibular reconstructions].

The authors present five cases where the OCLAF technique was adapted to reconstruct large mandibular defects. Some significant advantages made us think about the possibility of the OCLAF as an acceptable alternative in that specific case. These are the ease and safety of the dissection, the respect of a bony vascularisation, a very valuable pedicle size, and a remarkable mobility of the skin paddle to the underlying bone. Of course we had to face some minor disadvantages: the microsurgical procedure, the donor site scar, the absence of cancellous bone in the transfer and the weakening of the bone shaft at the donor site. Nevertheless we think the OCLAF is to be considered whenever large mandibular defects have to be reconstructed with vascularized bone.

Adult↗
PubMed1988

[Experience of decentralized informatics at a nephrology unit of a general hospital].

The computerized medical specialized records covering the follow-up of hypertension (ARTEMIS), diabetes (MELLITEE), chronic renal failure and the minimum medical record of Nephrology (THESEE) using the temporal database management system LIED, have been developed in several units of University Hospitals. The authors show that these computerized records are usable in a Nephrology Unit in a General Hospital.

Diabetes Mellitus↗
PubMed1987

Biphasic effect of quinolinate on frog spinal, but not rat cortical, neurones: N-methyl-D-aspartate-like depolarisation and a novel type of hyperpolarisation.

Using grease seal techniques on rat cerebral cortical slices and on frog hemisected spinal cords, bath applied N-methyl-D-aspartate (NMDA; 10-160 microM) and quinolinate (0.25-8 mM) induced dose-dependent depolarisations. These depolarising responses, but not those to quisqualate or kainate, were reduced by 2-amino-5-phosphono-valerate (2-AP5; 10-100 microM), magnesium (0.1-10 mM) and ketamine (10-100 microM). A novel dose-dependent hyperpolarising response to quinolinate (0.1-2 mM) but not to NMDA was observed only on frog motoneurones, and this was not reduced by classical amino acid receptor antagonists.

2-Amino-5-phosphonovalerate↗
PubMed1987

Metabolic alterations induced by hypoxia in the tortoise heart. Comparison between spongy and compact myocardium.

Experiments were performed to check the tolerance to severe hypoxia of the tissue layers (compact and spongy) of the tortoise heart. The animals were subjected to hypoxia (7% O2) at 18 degrees C, 28 degrees C and 38 degrees C for 30, 6 and 2 hr respectively, or to anoxia for 30 hr at 18 degrees C and 2 hr at 38 degrees C. At 18 degrees C the metabolic alterations caused by a 30 hr hypoxia were mild whereas at 28 degrees C and 38 degrees C the cardiac glycogen was depleted, lactate had accumulated and the phosphate creatine and ATP content had decreased. The extent of these metabolic changes was similar in the compact and in the spongy layers of the heart.

Adenosine Triphosphate↗
PubMed1987

A retrospective study of three treatment techniques for T1-T2 base of tongue lesions: surgery plus postoperative radiation, external radiation plus interstitial implantation and external radiation alone.

One hundred and ten patients with base of tongue tumors less than or equal to 4 cm in diameter (T1 and T2 by the UICC staging system) were treated according to three different methods; surgery followed by external radiation in 27 cases, external radiation followed by interstitial implantation in 29 cases, and external radiation alone in 54 cases. The median follow-up is 8 years with a minimum of 4 years. Local failure occurred twice as often in patients treated by external radiation alone (43%) compared to the other two therapeutic modalities (20.5% for external radiation plus implantation and 18.5% for surgery plus radiation). Ninety per cent of recurrences occurred within the first 2 years. The 5-year survival rate for N0 and N1 nodal disease is 30.5% for patients treated by external radiation alone and 50% for the other two methods. This survival difference is related to poorer local control. Surgery plus external radiation gives identical results to those of external radiation and interstitial implantation, but surgery is only practical for peripheral base of tongue tumors and it has poorer functional results. External radiation followed by interstitial implantation is, in our opinion, the best of the three therapeutic techniques for T1 and T2 base of tongue tumors.

Adult↗
PubMed1987

Long-term renal risk factors in children with meningomyelocele.

We studied renal function and structure in 42 patients with meningomyelocele, 28 treated with intermittent catheterization and 14 with ileal loop diversion. Patients were observed for a minimum of 60 months. Nine of the 28 patients who underwent intermittent catheterization had evidence of unilateral or bilateral reflux, and all patients with ileal loop diversion had free ureteral reflux. Bacteriuria was present in 38% +/- 5% of cultures obtained from patients with catheterization and in 70% +/- 7% of cultures from those with diversion (P less than 0.001). Four (14%) of 28 patients with catheterization had worsening renal function or anatomic appearance by intravenous pyelogram, and required a diversion. Three (28%) of 14 patients with diversion had changes in renal structure or function. Eight of 31 patients from both groups studied with voiding cystourethrography before the onset of therapy had small, noncompliant, trabeculated bladders; all seven patients who had worsening in function or anatomic appearance were from this subset (P less than 0.01). None of the patients with flaccid or distensible bladders demonstrated these changes. Renal disease was unrelated to the level of neurologic function. A small, noncompliant, trabeculated bladder is a risk factor associated with loss of renal function in patients with meningomyelocele.

Adult↗
PubMed1987

The lateral arm flap: an anatomic study.

The anatomy of the lateral arm flap is further elucidated, and the surgical techniques involved in raising the flap are described in detail. The data are derived from studies in 25 cadavers and five clinical cases. The relative merits of this versatile free flap are discussed. Three clinical cases are cited for illustration.

Amputation, Traumatic↗
PubMed1987

Amelioration of pulmonary pathophysiology of adult respiratory distress syndrome by sulindac, a cyclo-oxygenase inhibitor.

The effects of sulindac, a cyclo-oxygenase inhibitor, were tested in a bacteremic porcine model of acute respiratory failure produced by a continuous infusion of live Pseudomonas aeruginosa. Control groups received either a single intravenous dose of sulindac (6 mg/kg) 20 minutes after baseline determinations or a continuous infusion of Ps. aeruginosa (10(7) CFU/kg/min) beginning at time 0. The experimental group received both. Sulindac alone had no effect on any hemodynamic or gas exchange parameter. Ps. aeruginosa infusion caused pulmonary hypertension, hypoxemia, increased intrapulmonary shunt fraction, systemic hypotension, and increased extravascular lung water. Sulindac treatment reversed the pulmonary hypertension, hypoxemia, and increased intrapulmonary shunting, prevented the systemic hypotension, but had no effect on the rising extravascular lung water.

Animals↗
PubMed1987

The human placental alkaline phosphatase gene and related sequences map to chromosome 2 band q37.

A human placental alkaline phosphatase (PLAP) cDNA was isolated from a lambda gt 10 library of the cell line HEp-2. Southern blots probed with a fragment of the cDNA clone showed that the human genome may contain more than one PLAP-related sequence. The PLAP probe showed person-to-person variation in banding pattern with a number of enzymes. Using a panel of human/rodent somatic cell hybrids the PLAP sequences were mapped to chromosome 2. In situ hybridization confirmed this assignment and localized the gene(s) to chromosome 2 band q37.

Alkaline Phosphatase↗
PubMed1987

Lung morphological and permeability changes induced by intravascular coagulation in dogs.

The objectives of this study were to describe the morphological alterations of the pulmonary microvasculature in anesthetized dogs infused intravenously with alpha-thrombin (111-233 NIH U/kg) and to measure the protein reflection coefficient (sigma d), an index of pulmonary vascular permeability to proteins. Quantitative electron microscopy of lung biopsies from a group of four dogs showed an increase in the volume density of the alveolar interstitium and an increase in intravascular fibrin at 30 min after the thrombin infusion. The pulmonary microvascular endothelium was often swollen, blistered, highly vacuolized, or rarefied when close to or in contact with fibrin but appeared normal when not closely associated with fibrin. Fibrin-endothelial interactions often included projections of endothelium surrounding fibrin, the presence of fibrin within endothelial cells, 10- to 15-nm bridges connecting fibrin and endothelium, and disruption of the endothelial plasmalemma in contact with fibrin. Alveolar epithelial cells were unaffected by the thrombin infusion. Pulmonary lymph was collected from an afferent lymphatic to the left tracheobronchial lymph node in a second group of five dogs anesthetized with pentobarbital sodium intravenously. Thrombin increased pulmonary lymph flow by sevenfold and also increased the extravascular lung water-to-bloodless dry lung weight ratio. Left atrial pressure was elevated after thrombin infusion until a filtration-independent state was approached for the calculation of sigma d. Thrombin decreased sigma d from a normal value of 0.62 +/- 0.02 to 0.53 +/- 0.02. Thus thrombin-induced intravascular coagulation in dogs produced focal disruptions of the microvascular endothelium associated with intravascular fibrin and increased the pulmonary vascular permeability to proteins.

Animals↗